The invention relates to a rolling-mill installation for the continuous production of fine steel, especially wire, having roughing block, a finishing block arranged on the rolling line of the roughing block, a water cooling section arranged next and on the rolling line, and a laying unit arranged downstream.
Rolling-mill installations of this type are used for the conventional rolling of fine steel, especially of wire. In an installation of this type, for example one disclosed by EP B1 0 606 966, various paths, in which different rolling stands are arranged, can be passed through, depending on the desired final cross section of the rolled product and depending on the necessary final rolling temperature for the rolled material. The different paths are put into or out of operation by change-over devices for the rolled material--these are diverter-like components--, the rolled material on the one hand tracing relatively long or on the other hand tracing relatively short paths through the entire rolling-mill installation.
In recent times, the aim has been to achieve specific advantageous structure in the rolled material and therefore improved mechanical properties of the rolled material, which is implemented by means of thermomechanical rolling. In this case, following intensive surface cooling, the rolled material passes through a soaking section, in which far-reaching equalization of the temperature of the surface of the rolled material with the temperature of the core is carried out, so that for the subsequent deformation there is a largely homogenous temperature field within the cross section of the rolled material. Rolling-mill installations in which thermomechanical rolling is possible are disclosed, for example, by EP B1 0 264 868 and EP B1 0 560 115.
The drawback with installations of this type is, on the one hand, an extremely short soaking section, which does not permit adequate temperature equalization between core and surface, as a result of which thermomechanical rolling over the entire cross section cannot be achieved. On the other hand, adequate temperature equalization requires very long soaking sections, which in turn result in an extremely long design of the overall installation. In order to avoid these drawbacks, the rolled material has been led in a loop after emerging from the water cooling section and, after passing through the loop, has been finished in the finishing stand. An installation of this type is disclosed, for example, by EP B1 0 571 789. However, the drawback with an installation of this type is that during the rolling of small finished dimensions, as a result of the high number of passes, the reheating of the previously cooled material does not permit thermomechanical rolling.